In recent years, a service using AR (Augmented Reality) technology has been developed and provided. For example, a technique that acquires a virtual object placed in the vicinity of the located position of a mobile terminal and displays a virtual object including various information and images superimposed on a real-space image acquired by a camera mounted on the mobile terminal is known. Further, a technique that detects a specified marker from a real-space image acquired by a camera of a mobile terminal and displays a virtual object associated with the marker superimposed on the real-space image on a display is known. Furthermore, a technique that acquires three-dimensional map information including information about the shape or the like of a structure in the real space through communication, performs image analysis to obtain matching between the acquired map information and a real-space image acquired by a camera, and, when they match, displays a virtual object superimposed on the real-space image in association with a specified physical object existing in the real space is known. On the other hand, in order to suitably detect a marker from images taken under various conditions, a device that generates images of the marker with various colors, luminance, contrast, resolution and focus from a registered image of the marker and detects the marker based on the generated images is known (for example, see Patent Literature 1).